1. Field of the Invention
The present invention relates to a tandem image forming system in which a plurality of image forming apparatuses are serially connected, a sheet conveying device arranged between the image forming apparatuses, and a control method of the sheet conveying device.
2. Description of the Related Art
A tandem image forming system constituted by serially connecting two image forming apparatuses (hereinafter referred to simply as an “image forming system”) is known. According to the image forming system, when an image is to be formed on both surfaces of a sheet, an image is formed on the front surface of the sheet by the upstream image forming apparatus, and an image can be formed on the back surface of the sheet by the downstream image forming apparatus, for example. By sharing processing for forming images on the front surface and the back surface of the sheet by the respective image forming apparatuses, productivity can be improved as compared with formation of images on the both surfaces of the sheet with one image forming apparatus (see Japanese Patent Laid-Open No. 2012-143964).
In such type of the image forming system, a sheet conveying device might be arranged between the two image forming apparatuses. In the image forming system provided with the sheet conveying device, at occurrence of jamming, a work of removing the sheet in the sheet conveying device or the sheet conveyed to the sheet conveying device from the image forming apparatus arranged on the upstream side of the sheet conveying device is performed. Therefore, in such type of the sheet conveying device, a technology for removing the sheet easily is in demand.
On the other hand, a configuration has been proposed that the sheet conveying device is provided with a guide portion for opening a conveying path between two conveying rollers, and if jamming occurs, the guide portion is opened so as to eject the sheet being conveyed to an outside of the sheet conveying path (see Japanese Patent Laid-Open No. 2009-18923). In Japanese Patent Laid-Open No. 2009-18923, the sheet conveying device is configured to deflect the sheet by stopping or reverse feeding later the conveying roller on the downstream side and continuously forward feeding the conveying roller on the upstream side and to open the guide portion by pressing of the deflected sheet. As a result, the jammed sheet is automatically ejected to the outside of the sheet conveying path.